The present invention relates to a cordless or wireless telephone and, more particularly, to a switching system for use between the cordless telephone and an ordinary telephone.
A cordless telephone comprises a fixed unit which is connected to a telephone network through a subscriber line and a portable unit which is connected to the fixed unit. The fixed unit, is equipped with a telephone unit including a handset, and with a transmitter-receiver for radio communication with the portable unit over a radio channel. A subscriber of the portable unit can communicate through the fixed unit with a subscriber of an ordinary telephone connected to the telephone network.
Here, the telephone unit and the transmitter-receiver are supplied with power only from a common power source. If the common power supply is cut off by power failure or any other cause, the telephone unit of the fixed unit will become unusable and thus the communication using the telephone unit. the portable unit will be made impossible even though the telephone unit itself is operable.